Fuel pump



Nov. 12, 1935..A D. J. DEs`cHAMPs- FUEL PUMP Filed sept'. 19, 195o 2Sheets-Sheet l N2 12, ,1935- D. J. DESCHAMPS 2,020,302

FUEL PUMP Filed sept. 19,' 195o `2 sheets-sheet Patented .Nov. l2,17935A e UNITED STAT FUEL PUMP Desire J. Deschamps, St. Louis, Mo.,assigner of s PATlazN'r OFFICE This invention relates generally to fuelpumps, and m'ore particularly to that type of fuel pump which isemployed with a Diesel engine forl measuring each injection of fuel.

The fuel pumps heretofore employed in 'this relation have been providedwith a number of moving parts whereby to measure thequantity of fuelwhich is injected into the cylinder of the engine upon each stroke ofthe pump piston, and greatexpensefor upkeep of such pumps has beenencountered incident to the short life of such moving parts. In suchpumps of the prior art, which have not 'employed ,these auxiliary movingparts yfor measuring the quantity of fuel per injection and which havesought to measure the quantity of fuel by regulation of the length ofthe stroke of the plunger, economy and eiilciency have both beensacrificed, since the entire injection did not take place during themost rapid movement -of the pump piston in which the ygreatest pressureis applied to the fuel within the pump cylinder. Furthermore. the pumpspreviously used in industrial and heavy medium speed marine Dieselengines were not capable of operation at the unusually high speedsrequired in modern light small-sized automotive Diesel engines employedprincipally for automobile and aircraft purposes. Consequently, highoperating speeds of such engines, if not prohibited by the working ofthe pump, were found most unsatisfactory.

The object of this invention, therefore, is to provide a fuel pumpwhich'shall comprise a minimum number of moving parts and shall bepositive in operation.

vide a fuel pump in which the quantity of the fuel delivered therebyupon each stroke thereof is accurately measured. Amore specific objectof this invention is to provide a fuel pump in which the pressure uponthe fuel within the pump is released at a certain point. during thestroke of the piston to thereby limit the quantity of fuel delivered bythe pump. Another object of this invention is to.provide a fuel pump inwhich the injection takes place during the maximum speed of the pumppiston.

Another object of this invention is to provide a fuel pump for measuringthe quantity of fuel delivered and in which the injection always beginsat the same point in the movement thereof. Other objects willbecomeapparent to those skilled in the art when the following description isread -in conjunction with the accompanying drawings, in which:-

pump is at its suction or intake stroke.

Figure lis a front view shown partly in section to reveal the operatingparts of the pump of this invention;

Figure 2 is a bottom View shown partly in section, taken along line 2 2of Figure 1, and il- 5 lustratng in detail a device for regulating thequantity of fuel delivered by the pump;

Figure 3 is a sectional view, taken along the line 3--3 of Figure 1,'andshowingin detail a controlling valve; 10

`type of fuel pump can be built in units with single or multiplecylinder barrels and can be employed onall kinds of engines using fuelinjection, regardless of the cycle which is fol- 25 lowed.

v In accordance with this invention, a pair of fuel pumps are providedfor each cylinder of an internal combustion engineand the pumps areoperated at displacement, so that when one 30 pump is at the compressionstroke, the otlliler e two pumps are driven from a single cam shaftwhich operates at a speed equal to one-half the crank shaft speed oftheengine, and, accord- 35 ingly, an injection of fuel is delivered toeach cylinder ,of the engine upon each revolution thereof, although thefuel pumps are operated at but half the speed of the engine. Metering ofthe fuel by the pump itself is accomplished by 40 the provision of aduct through the pump piston to release the pressure of the confinedfuel Within the pump cylinder at a predetermined movement of the piston,thereby releasing the pressure on-the confined fuel and permitting the'45 operation of a spring valve to discontinue the injection of fuelinto the engine cylinder.

Referring now to the drawings, and more particularly to Figure 1, thereis shown a pump casing l, within which is provided a pair of parallel 50bores 2, each of the bores 2 receiving -a piston 3 which is slidablymounted and biased toward its'uppermost position by a plurality ofsprings I, and a cam shaft 5 is provided having a pair of cams 6, 1,which are disposed in directly oppo- 55 site relation-that is, so thatmembers actuated thereby will move in displacement. The cams 6 and 1 arearranged to cooperate respectively with the pistons 3 of the bores 2.With thereto. The reservoir 8 is connected by ducts I3 to a valve I2 andtherefrom by ducts 8 to the respective bores 2.

When the pump of this invention is operated I in the position shown,fuel enters the pump through I0 to ll the auxiliary reservoir 8- and thedifferentducts connected therewith. When, after its installation, fuelis for the first time supplied to the pump, air which has been trappedin the fuel line and in the pump will accumulate in the highest portionof the auxiliary reservoir 8, which portion is the bore for the valveI2.

This air, which would prevent proper operation of the pump, can readilybe released through a plug Ina.

It will be understood that if the fuel pump of this invention is to beused in an inverted position to that shown in the drawings, so that thecamshaft is operated beneath the pump, another" arrangement has to beused for admitting fuel to the pump. In this case a fuel connection willbe installed in place of the plug IIla and they accumulated air will bereleased at I0.

As clearly illustrated in Figure 3, the valve I2 comprises a tube havingan aperture I2a extend` ing through the wall thereof. In the` positionshown, the aperture I2a is in such position that fuel is admitted fromthe reservoir 8 through a duct I3 to the inside of valve I2 andconducted through the valve I2 to be delivered by aperture I2a to theduct 8 which leads to the bore 2 of the left pump cylinder. The valve I2may be rotated into another position in which the aperture I2a does notalign itself with the duct 8 to thereby interruptthe supply of fuel tothat side of .the pump without interfering with the supply of fuel tothe other side, which latteris in direct connection with the duct I3.

Within the bore- 2 is mounted a bushing I4 within which the piston orplunger 3 is movable so that this bushing. forms in effect the cylinderbarrel of the pump. The bushing I4 is provided with a plurality ofopenings I5, as clearly illustrated in Figure 3, which extend throughthe wall of the bushing to connect the groove II with the inside of thecylinder, and it is through these openings I5 that fuel is admitted tothe inside of the cylinder'from the reservoir andthe groove II. I5, anenlarged portion I6 is provided within the bushing, within which asupply of fuel may ac` cumulate, during the movement of the piston 3,

within the cylinder I4. l

The compression chamber oi the cylinder com prises a. recess I1 whichis, in effect, a groove similar to the groove I6 at the inlet port, butlwhich is formed between the bushing I4 and a co-operating gland memberI8, and a, duct I8 which leadsfroml the recess I1 to the valve or.ganization 2l, to be later described.

The gland I8, which co-operates with the bushing I4 and holds the latterin position, is pro- At the inner extremity of these openingsv videdwith a bore aligned with the bore within the bushing I4 but of smallerdiameter than the bore within the bushing I4, and it will be observedthat the plunger 3 is provided with an extended portion 22 of smallerdiameter than 5 the main portion thereof, so that a shoulder 23 isformed onA thc plunger or piston 3 and is movable within the boreof thebushing I4 to apply a pressure to the fuel confined within the cylinderbarrel I4 between the grooves I6 and I1, l0 at' which time the extendedportion 22 of the plunger 3 operates in conjunction with the gland I8 asa guide for the movement of the plunger. The extended portion 22 of theplunger is hollow, such as shown at 2,4, and a. hole 25 is cut 135through the wall thereof to connect the tube 24 to the outside oftheplunger near the shoulder 23 thereof, and similarly at the other endof the extended portion 22, a hole or outlet 28 is provided so thatthere exists a passageway 20 through the extended portion 22 of the.plunger from the cylinder, but this passageway has its outlet 26 closedduring the injection stroke of the piston by engagement with the Wall ofthe gland 21. Itis understood, of course, that a 25 plug is inserted inthe outer end of the tube 24 to prevent the escape of fuel through thatpath.

- 'Ihe gland 21 is provided around its inner wall with a groove 28 whichis in direct fluid connection thru passages 28 with the reservoir', 30and it willbe observed that when during the movement of the plunger 3with its extended portion 22, the o'utlet 26 comes into positionadjacent the groove 28, the outlet 26 will be opened i and permit thefuel within the cylinder `I4 to 35 flow outwardly through the passage 24and return to the reservoir 8.

About its outer surface, the gland 21 is pro- .vided with threads which.are in engagement with female threads upon a cooperating member 3I andat its upper portion the member 3I is provided about its periphery withgear teeth 32, as clearly illustrated in Figure 2,` which are disposedfor co-operation with a rack 33. The

vgland 21 is provided with a rib 21a, which is 45 splined to a cap 3l).It is thus clear that the gland 2 1 can be moved up and down under theaction of its adjusting mechanism, but is held against rotation relativeto the housing. It is thus apparent thatwhen the rack 33 is moved 50outwardly or inwardly, a rotation of the member 3| takes place, which,through the interacf tion of the threads within the member 3I and on theoutside of the gland 21, causes the gland 21 to move vertically andthereby effect a varia- 55 tion in the position of the groove 28 to-consequently vary the point in themovement of the piston at which theoutlet 26 will be opened to permit a release of the pressure upon thefuel confined within 4the cylinder I4 between the 60 grooves I6 and I1and in this way the measured quantity offuel delivered by the pump uponeach injection may be varied.

The outlet of the cylinder consists in a duct I9 leading into a recess34 and within this recess 34 65 is mounted the valve organization 2I,comprising Va. spring-loaded valve 35 which is normally held inengagement with its seat 36 by the operation of a spring 31. Thus, whensufficient pressure is applied to the fuel withinthe cylinder I4 be 70line 38, which leads tothe engine.' Moreover, 75

:,osooe when insufficient pressure is applied to the fuel confinedwithin the cylinder- I4 to force the valve open against the action ofthe spring 31, it willbe clearly seen that the supply of fuel to thefuel line 38 is positively cut off.

The operation of the pump 'may be readily understood by'reference toFigures 4 to k'1, inclusive. In Figure 4, the plunger 3 is illustratedwith the shoulder 23 in its topmost position at which the shoulder 2 3is disposed above the groove 4Hi of the cylinder and when the parts arein this position, fuel will be admitted through the openings I5 in thedirection of the arrow to fill all the recesses which are then connectedtherewith and which include openings l5, groove I8, groove l1, thatportion of the cylinder between the grooves I6 and I1, outlet I9, aswell as the tube 24y within the extended portion 22 of the plunger 3.When the parts are in 'this position, it will be clearly observed thatthe opening 26 is closed, since it is completely surrounded by the wallsof the gland 21, and accordingly no fuel can escape through this passagewhen the parts are in position illustrated in Figure 4. The parts remainin this position for a considerable perod of time, during which the camshaft rotates fromvthe position shown to the position in which the point39 comes into contact with the follower' 40, whereby the intake periodis lengthened to as- V sure that the cylinder becomes filled before thebeginning of the injection stroke. The rotation of the cam shaft is inthe ,direction indicated by the arrow so that downward movement of theplunger 3 commences at the position where the point 39 of the cam 6comes into contact with the follower 40, directly connected with thestem of the plunger 3, and' the plunger is moved into the position shownin Figure 5. In Figure 5, the position of the -plunger is such that thesupply of fuel from the inlet port I5 has just been cut ofi, sincev theshoulder 23 of the plunger is disposed just below the bottom edge of thegroove I6, and it is in this position that'pressure is first appled tothe fuel confined within the cylinder. It is to be observed that thegroove I6 isin fixed position relative to the body of the pump so thatthe beginning of the injection stroke will also take place at the samepoint in the movement of the piston, and consequently' the injection tothe engine will always occur. at the same Vtime during the cyclethereof. In Figure 5, it

fthe plunger traveling at its maximum speed, pressure is applied to thefuel conned within the cylinder, so that the valve 35 is forced open andthe fuel within the cylinder is forced outwardly through the duct'l9 andpast the valve 35, as illustrated in .Figure 1.

Figure 6 illustrates the pump parts in a position near 'the end o'f theinjection stroke. Although in Figure 6 the fuel is as yet underpressur-e, it will be observed that the bottom edge of the outlet 26 isadjacent to the upper edge of the groove 23 in the gland 21, so that theslightest further downward movement of the plunger will bring the outlet25 into contact with the groove 23 and open the passage through the tube24 to release the pressure upon the fuel conned within the cylinder andpermit the closure of valve 35 todiscontinue the supply of. fuel to theengine.A

In Figure 7, the parts are shown in that position in which the`outlet26has come into engagement with the groove 28 to open the passage 24through the extended portion 22 of theplunger 3 and to permit the escapeof fuel within the cyllo y in'der through the passage 24 during thelatter part of the downward movement of the plunger 3.

When the fuel is forced through the passage 24 and into the groove 28,itreturns to the reservoir 8 through the passage 29, as previouslydescribed. 1 5

When the plunger. 3 has reached its lowermost position, as illustratedin Figure 7, having completed an injectionstroke, the plunger is thenforced upwardly by the action of springs 4, which .upward m'ovement isrestrained by the cam 5 20 so that the upward movement of the plunger 3is gradual and a vacuum is created within the cylinder so that an inrushof'fuel occurs when the shoulder 23 with the plunger 3 again moves pastthe lower edge of the groove i6 to permit lowerxnost position, asillustrated, the-outlet 26 for the tube 24 has not yet come into contactwith the groove 2li,v so that no releaseA of the pressure upon the fuelconfined within the cylinder occurs when the gland 21 is adjusted inthis position. When the glandv 21 is disposed in position shown inFigure 8, the maximum volume of fuel is injected by the pump, since, asis clearly illustrated, the pressure upon the fuel is not released-40 bythe opening of outlet 26 even at the end of the stroke of the plunger 3.'I'he gland 21 may be moved upwardly to a position in which the outletA25 will lie adjacent the groove 28 when the plunger 3 is in theposition shown in Figure 5, and when 455 in such adjustmenait isapparent that n o fuel be forced through the valve 35, and accordinglythe motor may be stopped in this way. It, however, is to be distinctlyunderstood that the gland 21 may assume any position between that 50illustrated in Figure 8 and the stop position, so as to vary the chargeof fuel per stroke of the plunger 3, and it may well be pointed out thatalthough there are two pumps disposed within the casing I, the parts ofeach pump are identical 55 'with the parts 'of the other and that whenan adjustmentof the gland 21 for rone pump takes place, the sameadjustment of the gland 21 for -There being no reaction upon thismechanism, vthe rack 33 can be freely moved to regulate ythe output ofvthe pump under all speed and load conditions of the engine.

Since it is apparent that many modifications vwill present themselves tothose skilled in the art and that manysubcombinations are of utilitywhich shallnot depart from the spirit of this invention and the scope ofthe appended claima.`

it is to be distinctly understood that the embodiment here shown anddescribed shall be construed as merely illustrative and shall not be ltaken in a limiting sense.

Having thus described the invention, what is claimed is:l

1. In a fuel pump, a. cylinderlhaving a compression chamber providedwlth inlet and outlet l ports and a. reduced portionextending beyondsaid chamber, a plunger operable in said chamber having an extended partguided in said reduced portion of the cylinder and sealing the sameagainst the escape of fuel from. said chamber, said extended part havingan opening therethrough communicating with the chamber for permittingthe escape of fuel from said cylinder, and adjustable means engagingsaid extended part for closing said opening, said means having a,relieved portion adapted to cooperate with said opening at a.predetermined position of the plunger.

2; In a fuel pump, a cylinder provided with an inlet port in theperipheral wall thereof and an outlet port-therebeyond, a plunger havinga portion in sealing relation to the peripheral Wall of said cylinderandv movable therein across the inlet port, a by-pass through saidplunger, and by-pass controlling means adjustable to a xed position at avariable distance from the inlet and beyond said outlet port.

Patent No. '2, 026, 302.-

3.'In a fuel pump for internal combustion engines, a cylinder having acompression chamber connected to supply fuel to the engine andprovidedlwitn inlet and ouhet ports, a. p1unger having a shoulder at itsintermediate portion movable 5 across said inlet port to compress fuelin said chamber. said plunger having an exension beyond said outlet portprovided with a passage there.. along communicating with said chamber,and means adjustable to open the outer end of said 10 passage to relievethe pressure in said chamber v at a variable point in the stroke of saidplunger.

4. In an internal combustion engine, a fuel supply unit comprising, acasing, a pair of pumps housed in said casing, a fuel reservoir in saidcasl5 ing communicating with and providing the sole fuel supply for saidtwo pumps only; each of said pumps having a cylinder provided with acompression chamber connected to deliver fuel. to the engine, a plungeroperating in said chamber 20 having a ported, extended part guided in areduced portion of the cylinder and sealing same against escape of fuelfrom the chamber, and means cooperating with said ported plunger Yadapted to relieve the pressure in said compres- 25 sion chamber intosaid reservoir at a denite point in the stroke of said plunger; andmeans for operating said plungers in opposite time phase relation.

DESIRE J. DESCHAMPS.

November 12, 193s.

ursllu J. DESCHAMPS.'

i is hereby certified ihm crrorappears in the printed specification 0IVthe numbered patent requiring correction as loilows: Page v4, firstcolumn, me i5, claim i, after "pari" insert lhe words of said plunger;and that the said Letters Patent Ashould be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this l7th clay of December, A. D. 1935.

Seal) 4Leslie Frazer Acting Commissioner of Patents.

vention and the scope of the appended claima.`

it is to be distinctly understood that the embodiment here shown anddescribed shall be construed as merely illustrative and shall not be ltaken in a limiting sense.

Having thus described the invention, what is claimed is:l

1. In a fuel pump, a. cylinderlhaving a compression chamber providedwlth inlet and outlet l ports and a. reduced portionextending beyondsaid chamber, a plunger operable in said chamber having an extended partguided in said reduced portion of the cylinder and sealing the sameagainst the escape of fuel from. said chamber, said extended part havingan opening therethrough communicating with the chamber for permittingthe escape of fuel from said cylinder, and adjustable means engagingsaid extended part for closing said opening, said means having a,relieved portion adapted to cooperate with said opening at a.predetermined position of the plunger.

2; In a fuel pump, a cylinder provided with an inlet port in theperipheral wall thereof and an outlet port-therebeyond, a plunger havinga portion in sealing relation to the peripheral Wall of said cylinderandv movable therein across the inlet port, a by-pass through saidplunger, and by-pass controlling means adjustable to a xed position at avariable distance from the inlet and beyond said outlet port.

Patent No. '2, 026, 302.-

3.'In a fuel pump for internal combustion engines, a cylinder having acompression chamber connected to supply fuel to the engine andprovidedlwitn inlet and ouhet ports, a. p1unger having a shoulder at itsintermediate portion movable 5 across said inlet port to compress fuelin said chamber. said plunger having an exension beyond said outlet portprovided with a passage there.. along communicating with said chamber,and means adjustable to open the outer end of said 10 passage to relievethe pressure in said chamber v at a variable point in the stroke of saidplunger.

4. In an internal combustion engine, a fuel supply unit comprising, acasing, a pair of pumps housed in said casing, a fuel reservoir in saidcasl5 ing communicating with and providing the sole fuel supply for saidtwo pumps only; each of said pumps having a cylinder provided with acompression chamber connected to deliver fuel. to the engine, a plungeroperating in said chamber 20 having a ported, extended part guided in areduced portion of the cylinder and sealing same against escape of fuelfrom the chamber, and means cooperating with said ported plunger Yadapted to relieve the pressure in said compres- 25 sion chamber intosaid reservoir at a denite point in the stroke of said plunger; andmeans for operating said plungers in opposite time phase relation.

DESIRE J. DESCHAMPS.

November 12, 193s.

ursllu J. DESCHAMPS.'

i is hereby certified ihm crrorappears in the printed specification 0IVthe numbered patent requiring correction as loilows: Page v4, firstcolumn, me i5, claim i, after "pari" insert lhe words of said plunger;and that the said Letters Patent Ashould be read with this correctiontherein that the same may conform to the record of the case in thePatent Office.

Signed and sealed this l7th clay of December, A. D. 1935.

Seal) 4Leslie Frazer Acting Commissioner of Patents.

